The Inbox: Morphic-nice.1616.mcz

Nicolas Cellier uploaded a new version of Morphic to project The Inbox:
http://source.squeak.org/inbox/Morphic-nice.1616.mcz

==================== Summary ====================

Name: Morphic-nice.1616
Author: nice
Time: 8 January 2020, 10:48:52.680239 am
UUID: 88019e05-7d25-6744-97d0-4ebb873b6303
Ancestors: Morphic-mt.1615

Provide smoother scrolling in response to mouse wheel events

Instead of delivering the events when wheelDelta reaches 120, make this threshold a Preference (minimumWheelDelta)

Reminder: 120 represents a single notch for traditional mouse wheel with notches, but trackpads can deliver much smaller deltas

Rather than accumulating the wheelDeltas into MouseWheelState, do it when we #generateMouseWheelEvent:
Indeed, small deltas will come in packets of successive events, and it's more efficient to regroup then, exactly like we do with mouse trails...

Also MouseWheelState did ignore time outs (long delays between deltas) and other state changes (buttons/modifiers), which was not ideal.

Directly get those states from the raw eventBuffer, like any other mouse event. This requires integration of tose 2 PR:
https://github.com/OpenSmalltalk/opensmalltalk-vm/pull/461 for Windows
https://github.com/OpenSmalltalk/opensmalltalk-vm/pull/462 for OSX and linux

Honour larger wheelDeltas too in ScrollPane>>#mouseWheel: event handling
Honour horizontal mouse wheels too in ScrollPane
Note that the scroll pane still won't deliver sub-scrollDeltaWidth/scrollDeltaHeight with those changes, the number of scroll deltas is still rounded to 1.

With patched VM, and following settings, I get a reasonnable scrolling experience on OSX:

        HandMorph minimumWheelDelta: 20.
        Smalltalk sendMouseWheelEvents: true.

NOTE: it is tricky to add/remove inst. var. to such HandMorph because obsolete CompiledMethod pointing to old inst. var. offset are still active on the stack and can mess things up (unless you do not load the package from UI but rather from command line...).

Since accessing 'lastMouseEvent' in such obsolete CompiledMethod is causing grief, preserve its offset by swapping inst. var. order with 'targetOffset' which is less likely used.

=============== Diff against Morphic-mt.1615 ===============

Item was changed:
  Morph subclass: #HandMorph
+ instanceVariableNames: 'mouseFocus keyboardFocus eventListeners mouseListeners keyboardListeners eventCaptureFilters mouseCaptureFilters keyboardCaptureFilters mouseClickState mouseOverHandler targetOffset lastMouseEvent damageRecorder cacheCanvas cachedCanvasHasHoles temporaryCursor temporaryCursorOffset hardwareCursor hasChanged savedPatch userInitials lastEventBuffer genieGestureProcessor keyboardInterpreter'
+ classVariableNames: 'CompositionWindowManager DoubleClickTime DragThreshold EventStats MinimalWheelDelta NewEventRules NormalCursor PasteBuffer SendMouseWheelToKeyboardFocus ShowEvents SynthesizeMouseWheelEvents'
- instanceVariableNames: 'mouseFocus keyboardFocus eventListeners mouseListeners keyboardListeners eventCaptureFilters mouseCaptureFilters keyboardCaptureFilters mouseClickState mouseOverHandler mouseWheelState lastMouseEvent targetOffset damageRecorder cacheCanvas cachedCanvasHasHoles temporaryCursor temporaryCursorOffset hardwareCursor hasChanged savedPatch userInitials lastEventBuffer genieGestureProcessor keyboardInterpreter'
- classVariableNames: 'CompositionWindowManager DoubleClickTime DragThreshold EventStats NewEventRules NormalCursor PasteBuffer SendMouseWheelToKeyboardFocus ShowEvents SynthesizeMouseWheelEvents'
  poolDictionaries: 'EventSensorConstants'
  category: 'Morphic-Kernel'!
 
  !HandMorph commentStamp: '<historical>' prior: 0!
  The cursor may be thought of as the HandMorph.  The hand's submorphs hold anything being carried by dragging.  
 
  There is some minimal support for multiple hands in the same world.!

Item was added:
+ ----- Method: HandMorph class>>minimumWheelDelta (in category 'preferences') -----
+ minimumWheelDelta
+ <preference: 'Minimal Mouse Wheel Detection Threshold'
+ categoryList: #(Morphic mouse)
+ description: 'Answer the minimal scrolling units taken into account
+ Defaults to 120 (See #scrollUnitsPerMouseWheelNotch), corresponding to a single mouse wheel notch.
+ Use a lower value (20 - See #minimalScrollUnitsPerEvent) if wanting smoother scrolling with trackpads.'
+ type: #Number>
+ ^MinimalWheelDelta ifNil: [MouseWheelEvent scrollUnitsPerMouseWheelNotch].!

Item was added:
+ ----- Method: HandMorph class>>minimumWheelDelta: (in category 'preferences') -----
+ minimumWheelDelta: anInteger
+ MinimalWheelDelta := anInteger ifNotNil: [anInteger
+ clampLow: MouseWheelEvent minimalScrollUnitsPerEvent
+ high: MouseWheelEvent scrollUnitsPerMouseWheelNotch]!

Item was changed:
  ----- Method: HandMorph>>generateMouseWheelEvent: (in category 'private events') -----
  generateMouseWheelEvent: evtBuf
  "Generate the appropriate mouse wheel event for the given raw event buffer"
 
+ | buttons modifiers deltaX deltaY stamp nextEvent |
- | buttons modifiers deltaX deltaY stamp |
  stamp := evtBuf second.
  stamp = 0 ifTrue: [stamp := Time eventMillisecondClock].
  deltaX := evtBuf third.
  deltaY := evtBuf fourth.
+ buttons := evtBuf fifth.
+ modifiers := evtBuf sixth.
+ [(deltaX abs + deltaY abs < self class minimumWheelDelta)
+ and: [(nextEvent := Sensor peekEvent) notNil
+ and: [nextEvent first = evtBuf first
+ and: [nextEvent fifth = evtBuf fifth
+ and: [nextEvent sixth = evtBuf sixth]
+ and: [nextEvent third isZero = evtBuf third isZero "both horizontal or vertical"]]]]]
+ whileTrue:
+ ["nextEvent is similar.  Remove it from the queue, and check the next."
+ nextEvent := Sensor nextEvent.
+ deltaX := deltaX + nextEvent third.
+ deltaY := deltaY + nextEvent fourth].
- modifiers := evtBuf fifth.
- buttons := (modifiers bitShift: 3) bitOr: (lastMouseEvent buttons bitAnd: 7).
  ^ MouseWheelEvent new
  setType: #mouseWheel
  position: self position
  delta: deltaX@deltaY
- direction: 2r0000
  buttons: buttons
  hand: self
  stamp: stamp!

Item was changed:
  ----- Method: HandMorph>>generateMouseWheelEvent:direction: (in category 'private events') -----
  generateMouseWheelEvent: keystrokeEvent direction: direction
  "Generate the appropriate mouse wheel event from the keystrokeEvent. Before calling this, ensure that the control key is pressed.
 
  This method can be discarded once the VM produces real mouse wheel events."
 
  ^ MouseWheelEvent new
  setType: #mouseWheel
  position: keystrokeEvent position
+ delta: 0 @ ((direction anyMask: 2r1000 "wheel up") ifTrue: [MouseWheelEvent scrollUnitsPerMouseWheelNotch] ifFalse: [MouseWheelEvent scrollUnitsPerMouseWheelNotch negated])
- delta: 0 @ ((direction anyMask: 2r1000 "wheel up") ifTrue: [120] ifFalse: [-120])
  direction: direction
  buttons: (keystrokeEvent buttons bitAnd: 2r01111) "drop control key pressed for this conversion"
  hand: keystrokeEvent hand
  stamp: keystrokeEvent timeStamp!

Item was changed:
  ----- Method: HandMorph>>handleEvent: (in category 'events-processing') -----
  handleEvent: unfilteredEvent
 
  | filteredEvent |
  owner ifNil: [^ unfilteredEvent  "not necessary but good style -- see Morph >> #handleEvent:"].
 
  self logEvent: unfilteredEvent.
 
  "Mouse-over events occur really, really, really often. They are kind of the heart beat of the Morphic UI process."
  unfilteredEvent isMouseOver ifTrue: [^ self sendMouseEvent: unfilteredEvent].
 
  self showEvent: unfilteredEvent.
  self sendListenEvents: unfilteredEvent.
 
  filteredEvent := self sendFilterEventCapture: unfilteredEvent for: nil.
  "filteredEvent := unfilteredEvent" " <-- use this to disable global capture filters"
 
  filteredEvent wasIgnored ifTrue: [
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  filteredEvent isWindowEvent ifTrue: [
  self sendEvent: filteredEvent focus: nil.
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  filteredEvent isKeyboard ifTrue:[
  self sendKeyboardEvent: filteredEvent.
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  filteredEvent isDropEvent ifTrue:[
  self sendEvent: filteredEvent focus: nil.
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  filteredEvent isMouse ifFalse: [
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  " ********** MOUSE EVENT *********** "
 
  lastMouseEvent := filteredEvent.
 
  "Check for pending drag or double click operations."
  mouseClickState ifNotNil:[
  (mouseClickState handleEvent: filteredEvent from: self) ifFalse:[
  "Possibly dispatched #click: or something and will not re-establish otherwise"
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent]].
 
  filteredEvent isMouseWheel ifTrue: [
+ self class sendMouseWheelToKeyboardFocus
+ ifFalse: [self sendMouseEvent: filteredEvent]
+ ifTrue: [self sendEvent: filteredEvent focus: self keyboardFocus clear: [self keyboardFocus: nil]].
- mouseWheelState ifNil: [mouseWheelState := MouseWheelState new].
- mouseWheelState handleEvent: filteredEvent from: self.
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  filteredEvent isMove ifTrue:[
  self position: filteredEvent position.
  self sendMouseEvent: filteredEvent.
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent].
 
  "Issue a synthetic move event if we're not at the position of the event"
  filteredEvent position = self position
  ifFalse: [self moveToEvent: filteredEvent].
 
  "Drop submorphs on button events"
  self hasSubmorphs
  ifTrue:[self dropMorphs: filteredEvent]
  ifFalse:[self sendMouseEvent: filteredEvent].
 
  self mouseOverHandler processMouseOver: lastMouseEvent.
  ^ filteredEvent "not necessary but good style -- see Morph >> #handleEvent:" !

Item was added:
+ ----- Method: MouseWheelEvent class>>convertScrollUnits:intoScrollDelta: (in category 'utility') -----
+ convertScrollUnits: scrollUnits intoScrollDelta: scrollDeltaPerMouseWheelNotch
+ "Convert the scrolling units provided by the VM into scrolling delta (increment) used by Morph.
+ The morph knows how many scroll delta it wants per single wheel notch.
+ I know how many scrolling units is generated by a single wheel notch."
+
+ ^scrollUnits abs * scrollDeltaPerMouseWheelNotch // self scrollUnitsPerMouseWheelNotch max: 1!

Item was added:
+ ----- Method: MouseWheelEvent class>>minimalScrollUnitsPerEvent (in category 'constants') -----
+ minimalScrollUnitsPerEvent
+ "Answer how many scroll units a single mouse wheel event can generate.
+ This reflects a value hardcoded in the VM.
+ The VM aggregate wheel events until this threshold is reached."
+
+ ^20!

Item was added:
+ ----- Method: MouseWheelEvent class>>scrollUnitsPerMouseWheelNotch (in category 'constants') -----
+ scrollUnitsPerMouseWheelNotch
+ "Answer how many scroll units a single mouse wheel notch does generate.
+ This reflects a value hardcoded in the VM.
+ The value is chosen high enough so as to enable:
+ - smoother scrolling on notch-less devices.
+ - while preserving Integer arithmetic
+ Interpretation (scaling) of scrolling units is left to the client morphs.
+ Typically, 120 units (1 notch) represents 3 lines of text."
+
+ ^120!

Item was added:
+ ----- Method: MouseWheelEvent>>horizontalScrollDelta: (in category 'accessing') -----
+ horizontalScrollDelta: scrollDeltaPerMouseWheelNotch
+ "Convert scrolling units into unsigned scrolling increment.
+ The morph knows how many scroll delta it wants per single wheel notch.
+ Note that returned increment value is always positive, regardless of direction."
+ ^self class convertScrollUnits: delta x intoScrollDelta: scrollDeltaPerMouseWheelNotch!

Item was added:
+ ----- Method: MouseWheelEvent>>setDirection (in category 'initialization') -----
+ setDirection
+ delta x > 0 ifTrue: [self setWheelRight].
+ delta x < 0 ifTrue: [self setWheelLeft].
+
+ delta y > 0 ifTrue: [self setWheelUp].
+ delta y < 0 ifTrue: [self setWheelDown].!

Item was added:
+ ----- Method: MouseWheelEvent>>setType:position:delta:buttons:hand:stamp: (in category 'private') -----
+ setType: evtType position: evtPos delta: evtDelta buttons: evtButtons hand: evtHand stamp: stamp
+ type := evtType.
+ position := evtPos.
+ buttons := evtButtons.
+ source := evtHand.
+ wasHandled := false.
+ direction := 2r0000.
+ delta := evtDelta.
+ timeStamp := stamp.
+ self setDirection!

Item was added:
+ ----- Method: MouseWheelEvent>>verticalScrollDelta: (in category 'accessing') -----
+ verticalScrollDelta: scrollDeltaPerMouseWheelNotch
+ "Convert scrolling units into unsigned scrolling increment.
+ The morph knows how many scroll delta it wants per single wheel notch.
+ Note that returned increment value is always positive, regardless of direction."
+ ^self class convertScrollUnits: delta y intoScrollDelta: scrollDeltaPerMouseWheelNotch!

Item was removed:
- Object subclass: #MouseWheelState
- instanceVariableNames: 'currentDelta'
- classVariableNames: ''
- poolDictionaries: ''
- category: 'Morphic-Events'!

Item was removed:
- ----- Method: MouseWheelState>>handleEvent:from: (in category 'event processing') -----
- handleEvent: aMouseWheelEvent from: aHand
- "Every 120 units, raise the wheel flags for convenient mouse wheel programming. We choose not to send multiple mouse-wheel events for multiples of 120 because applications can always react to the actual delta values if they want to do more scrolling or zooming."
-
- | sign |
- currentDelta := currentDelta + aMouseWheelEvent wheelDelta.
-
- sign := currentDelta sign.
- currentDelta := currentDelta abs.
-
- (currentDelta x // 120) > 0 ifTrue: [
- sign x = 1
- ifTrue: [aMouseWheelEvent setWheelRight]
- ifFalse: [aMouseWheelEvent setWheelLeft]].
-
- (currentDelta y // 120) > 0 ifTrue: [
- sign y = 1
- ifTrue: [aMouseWheelEvent setWheelUp]
- ifFalse: [aMouseWheelEvent setWheelDown]].
-
- currentDelta := currentDelta \\ 120.
- currentDelta := currentDelta * sign.
-
- "Finally, send the event."
- HandMorph sendMouseWheelToKeyboardFocus
- ifFalse: [aHand sendMouseEvent: aMouseWheelEvent]
- ifTrue: [aHand sendEvent: aMouseWheelEvent focus: aHand keyboardFocus clear: [aHand keyboardFocus: nil]].
- !

Item was removed:
- ----- Method: MouseWheelState>>initialize (in category 'initialize-release') -----
- initialize
-
- super initialize.
- currentDelta := 0@0.!

Item was changed:
  MorphicModel subclass: #ScrollPane
  instanceVariableNames: 'scrollBar scroller retractableScrollBar scrollBarOnLeft getMenuSelector getMenuTitleSelector hasFocus hScrollBar hScrollBarPolicy vScrollBarPolicy scrollBarThickness'
+ classVariableNames: 'HorizontalScrollDeltaPerMouseWheelNotch UseRetractableScrollBars VerticalScrollDeltaPerMouseWheelNotch'
- classVariableNames: 'UseRetractableScrollBars'
  poolDictionaries: ''
  category: 'Morphic-Windows'!
 
  !ScrollPane commentStamp: 'mk 8/9/2005 10:34' prior: 0!
  The scroller (a transform) of a scrollPane is driven by the scrollBar.  The scroll values vary from 0.0, meaning zero offset to 1.0 meaning sufficient offset such that the bottom of the scrollable material appears 3/4 of the way down the pane.  The total distance to achieve this range is called the totalScrollRange.
 
  Basic clue about utilization of the ScrollPane class is given in:
  ScrollPane example1.
  ScrollPane example2.!

Item was added:
+ ----- Method: ScrollPane class>>horizontalScrollDeltaPerMouseWheelNotch (in category 'preferences') -----
+ horizontalScrollDeltaPerMouseWheelNotch
+
+ <preference: 'horizontal scroll increment per single mouse wheel'
+ category: #scrolling
+ description: 'How many horizontal scroll increments should be caused in response to a single mouse wheel notch.
+ Typically, the scroll panes increment are about 1 character width for list and text panes (see #scrollDeltaWidth).
+ The default setting is 3 so as to match the most widely used convention.'
+ type: #Number>
+ ^ HorizontalScrollDeltaPerMouseWheelNotch ifNil: [3]!

Item was added:
+ ----- Method: ScrollPane class>>horizontalScrollDeltaPerMouseWheelNotch: (in category 'preferences') -----
+ horizontalScrollDeltaPerMouseWheelNotch: anIntegerOrNil
+
+ HorizontalScrollDeltaPerMouseWheelNotch := anIntegerOrNil!

Item was added:
+ ----- Method: ScrollPane class>>verticalScrollDeltaPerMouseWheelNotch (in category 'preferences') -----
+ verticalScrollDeltaPerMouseWheelNotch
+
+ <preference: 'vertical scroll increment per single mouse wheel'
+ category: #scrolling
+ description: 'How many vertical scroll increments should be caused in response to a single mouse wheel notch.
+ Typically, the scroll panes increment are one line height for list and text panes (see #scrollDeltaHeight).
+ The default setting is 3 so as to match the most widely used convention.'
+ type: #Number>
+ ^ VerticalScrollDeltaPerMouseWheelNotch ifNil: [3]!

Item was added:
+ ----- Method: ScrollPane class>>verticalScrollDeltaPerMouseWheelNotch: (in category 'preferences') -----
+ verticalScrollDeltaPerMouseWheelNotch: anIntegerOrNil
+
+ VerticalScrollDeltaPerMouseWheelNotch := anIntegerOrNil!

Item was changed:
  ----- Method: ScrollPane>>mouseWheel: (in category 'event handling') -----
  mouseWheel: evt
 
+ evt isWheelUp ifTrue: [scrollBar scrollUp: (evt verticalScrollDelta: self class verticalScrollDeltaPerMouseWheelNotch)].
+ evt isWheelDown ifTrue: [scrollBar scrollDown: (evt verticalScrollDelta: self class verticalScrollDeltaPerMouseWheelNotch)].
+ evt isWheelLeft ifTrue: [hScrollBar scrollUp: (evt horizontalScrollDelta: self class verticalScrollDeltaPerMouseWheelNotch)].
+ evt isWheelRight ifTrue: [hScrollBar scrollDown: (evt horizontalScrollDelta: self class verticalScrollDeltaPerMouseWheelNotch)].!
- evt isWheelUp ifTrue: [scrollBar scrollUp: 3].
- evt isWheelDown ifTrue: [scrollBar scrollDown: 3].!